Continuously variable transmission

ABSTRACT

A continuously variable transmission is disclosed for use in rotationally or linearly powered machines and vehicles. The transmission provides a simple manual shifting method for the user. Further, the practical commercialization of traction roller transmissions requires improvements in the reliability, ease of shifting, function and simplicity of the transmission. The present invention includes a continuously variable transmission that may be employed in connection with any type of machine that is in need of a transmission. For example, the transmission may be used in (i) a motorized vehicle such as an automobile, motorcycle, or watercraft, (ii) a non-motorized vehicle such as a bicycle, tricycle, scooter, exercise equipment or (iii) industrial equipment, such as a drill press, power generating equipment, or textile mill.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S.application Ser. No. 10/770,966 filed on Feb. 3, 2004, which claimspriority from U.S. application Ser. No. 10/134,097 filed on Apr. 25,2002, which in turn claims priority from U.S. Provisional ApplicationNo. 60/286,803, filed Apr. 26, 2001. The entire disclosure of each ofthose applications is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention relates generally to transmissions, and moreparticularly the invention relates to continuously variabletransmissions.

2. Description of the Related Art

The present invention relates to the field of continuously variabletransmissions and includes several novel features and inventive aspectsthat have been developed and are improvements upon the prior art. Inorder to provide an infinitely variable transmission, various tractionroller transmissions in which power is transmitted through tractionrollers supported in a housing between torque input and output diskshave been developed. In such transmissions, the traction rollers aremounted on support structures which, when pivoted, cause the engagementof traction rollers with the torque disks in circles of varyingdiameters depending on the desired transmission ratio.

However, the success of these traditional solutions has been limited.For example, in one solution, a driving hub for a vehicle with avariable adjustable transmission ratio is disclosed. This method teachesthe use of two iris plates, one on each side of the traction rollers, totilt the axis of rotation of each of the rollers. However, the use ofiris plates can be very complicated due to the large number of partsthat are required to adjust the iris plates during transmissionshifting. Another difficulty with this transmission is that it has aguide ring that is configured to be predominantly stationary in relationto each of the rollers. Since the guide ring is stationary, shifting theaxis of rotation of each of the traction rollers is difficult.

One improvement over this earlier design includes a shaft about which adriving member and a driven member rotate. The driving member and drivenmember are both mounted on the shaft and contact a plurality of poweradjusters disposed equidistantly and radially about the shaft. The poweradjusters are in frictional contact with both members and transmit powerfrom the driving member to the driven member. A support member locatedconcentrically over the shaft and between the power adjusters applies aforce to keep the power adjusters separate so as to make frictionalcontact against the driving member and the driven member. A limitationof this design is the absence of means for generating an adequate axialforce to keep the driving and driven members in sufficient frictionalcontact against the power adjusters as the torque load on thetransmission changes. A further limitation of this design is thedifficulty in shifting that results at high torque and very low speedsituations as well as insufficient means for disengaging thetransmission and coasting.

Therefore, there is a need for a continuously variable transmission withan improved power adjuster support and shifting mechanism, means ofapplying proper axial thrust to the driving and driven members forvarious torque and power loads, and means of disengaging and reengagingthe clutch for coasting.

SUMMARY OF THE INVENTION

The systems and methods have several features, no single one of which issolely responsible for its desirable attributes. Without limiting thescope as expressed by the claims that follow, its more prominentfeatures will now be discussed briefly. After considering thisdiscussion, and particularly after reading the section entitled“Detailed Description of the Preferred Embodiments” one will understandhow the features of the system and methods provide several advantagesover traditional systems and methods.

In one aspect, a continuously variable transmission is disclosed havinga longitudinal axis, and a plurality of speed adjusters. Each speedadjuster has a tiltable axis of rotation is located radially outwardfrom the longitudinal axis. Also provided are a drive disk that isannularly rotatable about the longitudinal axis and also contacts afirst point on each of the speed adjusters and a support member that isalso annularly rotatable about the longitudinal axis. A bearing disk isprovided that is annularly rotatable about the longitudinal axis aswell, and at least two axial force generators. The axial forcegenerators are located between the drive disk and the bearing disk andeach axial force generator is configured to apply an axial force to thedrive disk.

In another aspect, a bearing disk annularly rotatable about thelongitudinal axis is disclosed along with a disengagement mechanism. Thedisengagement mechanism can be positioned between the bearing disk andthe drive disk and is adapted to cause the drive disk to disengage thedrive disk from the speed adjusters.

In yet another aspect, an output disk or rotatable hub shell isdisclosed along with a bearing disk that is annularly rotatable aboutthe longitudinal axis of the transmission. A support member is includedthat is annularly rotatable about the longitudinal axis as well, and isadapted to move toward whichever of the drive disk or the output disk isrotating more slowly.

In still another aspect, a linkage subassembly having a hook isdisclosed, wherein the hook is attached to either the drive disk or thebearing disk. Included is a latch attached to either the drive disk orand the bearing disk.

In another aspect, a plurality of spindles having two ends is disclosed,wherein one spindle is positioned in the bore of each speed adjuster anda plurality of spindle supports having a platform end and spindle end isprovided. Each spindle support is operably engaged with one of the twoends of one of the spindles. Also provided is a plurality of spindlesupport wheels, wherein at least one spindle support wheel is providedfor each spindle support. Included are annular first and secondstationary supports each having a first side facing the speed adjustersand a second side facing away from the speed adjusters. Each of thefirst and second stationary supports have a concave surface on the firstside and the first stationary support is located adjacent to the drivedisk and the second stationary support is located adjacent to the drivendisk.

Also disclosed is a continuously variable transmission having a coiledspring that is positioned between the bearing disk and the drive disk.

In another aspect, a transmission shifting mechanism is disclosedcomprising a rod, a worm screw having a set of external threads, ashifting tube having a set of internal threads, wherein a rotation ofthe shifting tube causes a change in the transmission ratio, a sleevehaving a set of internal threads, and a split shaft having a threadedend.

In yet another aspect, a remote transmission shifter is disclosedcomprising a rotatable handlegrip, a tether having a first end and asecond end, wherein the first end is engaged with the handlegrip and thesecond end is engaged with the shifting tube. The handlegrip is adaptedto apply tension to the tether, and the tether is adapted to actuate theshifting tube upon application of tension.

These and other improvements will become apparent to those skilled inthe art as they read the following detailed description and view theenclosed figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway side view of an embodiment of the transmission.

FIG. 2 is a partial end cross-sectional view taken on line II-II of FIG.1.

FIG. 3 is a perspective view of a split shaft and two stationarysupports of the transmission of FIG. 1.

FIG. 4 is a schematic cutaway side view of the transmission of FIG. 1shifted into low.

FIG. 5 is a schematic cutaway side view of the transmission of FIG. 1shifted into high.

FIG. 6 is a schematic side view of a ramp bearing positioned between twocurved ramps of the transmission of FIG. 1.

FIG. 7 is a schematic side view of a ramp bearing positioned between twocurved ramps of the transmission of FIG. 1.

FIG. 8 is a schematic side view of a ramp bearing positioned between twocurved ramps of the transmission of FIG. 1.

FIG. 9 is a perspective view of the power adjuster sub-assembly of thetransmission of FIG. 1.

FIG. 10 is a cutaway perspective view of the shifting sub-assembly ofthe transmission of FIG. 1.

FIG. 11 is a perspective view of a stationary support of thetransmission of FIG. 1.

FIG. 12 is a perspective view of the screw and nut of the transmissionof FIG. 1.

FIG. 13 is a schematic perspective view of the frame support of thetransmission of FIG. 1.

FIG. 14 is a partial cutaway perspective view of the central ramps ofthe transmission of FIG. 1.

FIG. 15 is a perspective view of the perimeter ramps of the transmissionof FIG. 1.

FIG. 16 is a perspective view of the linkage sub-assembly of thetransmission of FIG. 1.

FIG. 17 is a perspective view of the disengagement mechanismsub-assembly of the transmission of FIG. 1.

FIG. 18 is a perspective view of the handlegrip shifter of thetransmission of FIG. 1.

FIG. 19 is a cutaway side view of an alternative embodiment of thetransmission of FIG. 1.

FIG. 20 is a cutaway side view of yet another alternative embodiment ofthe transmission of FIG. 1.

FIG. 21 is a perspective view of the transmission of FIG. 20 depicting atorsional brace.

FIG. 22 is a perspective view of an alternative disengagement mechanismof the transmission of FIG. 1.

FIG. 23 is another perspective view of the alternative disengagementmechanism of FIG. 22.

FIG. 24 is a view of a sub-assembly of an alternative embodiment of theaxial force generators of the transmission of FIG. 20.

FIG. 25 is a schematic cross sectional view of the splines and groovesof the axial force generators of FIG. 24.

FIG. 26 is a perspective view of an alternative disengagement mechanismof the transmission of FIG. 1.

FIG. 27 is a perspective view of the alternative disengagement mechanismof FIG. 26.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the invention will now be described with reference to theaccompanying figures, wherein like numerals refer to like elementsthroughout. The terminology used in the description presented herein isnot intended to be interpreted in any limited or restrictive mannersimply because it is being utilized in conjunction with a detaileddescription of certain specific embodiments of the invention.Furthermore, embodiments of the invention may include several novelfeatures, no single one of which is solely responsible for its desirableattributes or which is essential to practicing the inventions hereindescribed.

The transmissions described herein are of the type that utilize speedadjuster balls with axes that tilt as described in U.S. patentapplication Ser. No. 09/695,757, filed on Oct. 24, 2000 and theinformation disclosed in that application is hereby incorporated byreference for all that it discloses. A drive (input) disk and a driven(output) disk are in contact with the speed adjuster balls. As the ballstilt on their axes, the point of rolling contact on one disk movestoward the pole or axis of the ball, where it contacts the ball at acircle of decreasing diameter, and the point of rolling contact on theother disk moves toward the equator of the ball, thus contacting thedisk at a circle of increasing diameter. If the axis of the ball istilted in the opposite direction, the disks respectively experience theconverse situation. In this manner, the ratio of rotational speed of thedrive disk to that of the driven disk, or the transmission ratio, can bechanged over a wide range by simply tilting the axes of the speedadjuster balls.

With reference to the longitudinal axis of embodiments of thetransmission, the drive disk and the driven disk can be located radiallyoutward from the speed adjuster balls, with an idler-type generallycylindrical support member located radially inward from the speedadjuster balls, so that each ball makes three-point contact with theinner support member and the outer disks. The drive disk, the drivendisk, and the support member can all rotate about the same longitudinalaxis. The drive disk and the driven disk can be shaped as simple disksor can be concave, convex, cylindrical or any other shape, depending onthe configuration of the input and output desired. The rolling contactsurfaces of the disks where they engage the speed adjuster balls canhave a flat, concave, convex or other profile, depending on the torqueand efficiency requirements of the application.

Referring to FIGS. 1 and 2, an embodiment of a continuously variabletransmission 100 is disclosed. The transmission 100 is shrouded in a hubshell 40, which functions as an output disk and is desirable in variousapplications, including those in which a vehicle (such as a bicycle ormotorcycle) has the transmission contained within a driven wheel. Thehub shell 40 can, in certain embodiments, be covered by a hub cap 67. Atthe heart of the transmission 100 are a plurality of speed adjusters 1that can be spherical in shape and are circumferentially spaced more orless equally or symmetrically around the centerline, or axis ofrotation, of the transmission 100. In the illustrated embodiment, eightspeed adjusters 1 are used. However, it should be noted that more orfewer speed adjusters 1 can be used depending on the use of thetransmission 100. For example, the transmission may include 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15 or more speed adjusters. The provisionfor more than 3, 4, or 5 speed adjusters can provide certain advantagesincluding, for example, widely distributing the forces exerted on theindividual speed adjusters 1 and their points of contact with othercomponents of the transmission 100. Certain embodiments in applicationswith low torque but a high transmission ratio can use few speedadjusters 1 but large speed adjusters 1, while certain embodiments inapplications where high torque and a transmission high transmissionratio can use many speed adjusters 1 and large speed adjusters 1. Otherembodiments in applications with high torque and a low transmissionratio can use many speed adjusters 1 and small speed adjusters 1.Finally, certain embodiments in applications with low torque and a lowtransmission ratio may use few speed adjusters 1 and small speedadjusters 1.

Spindles 3 are inserted through holes that run through the center ofeach of the speed adjusters 1 to define an axis of rotation for each ofthe speed adjusters 1. The spindles 3 are generally elongated shaftsabout which the speed adjusters 1 rotate, and have two ends that extendout of either end of the hole through the speed adjusters 1. Certainembodiments will have cylindrical shaped spindles 3, though any shapecan be used. The speed adjusters 1 are mounted to freely rotate aboutthe spindles 3. In FIG. 1, the axes of rotation of the speed adjusters 1are shown in an approximately horizontal direction (i.e., parallel tothe main axis of the transmission 100).

FIGS. 1, 4 and 5, can be utilized to describe how the axes of the speedadjusters 1 can be tilted in operation to shift the transmission 100.FIG. 4 depicts the transmission 100 shifted into a low transmissionratio, or low, while FIG. 5 depicts the transmission 100 shifted into ahigh transmission ratio, or high. Now also referring to FIGS. 9 and 10,a plurality of spindle supports 2 are attached to the spindles 3 neareach of the ends of the spindles 3 that extend out of the holes boredthrough the speed adjusters 1, and extend radially inward from thosepoints of attachment toward the axis of the transmission 100. In oneembodiment, each of the spindle supports 2 has a through bore thatreceives one end of one of the spindles 3. The spindles 3 preferablyextend through and beyond the spindle supports 2 such that they have anexposed end. In the embodiments illustrated, the spindles 3advantageously have spindle rollers 4 coaxially and slidingly positionedover the exposed ends of the spindles 3. The spindle rollers 4 aregenerally cylindrical wheels fixed axially on the spindles 3 outside ofand beyond the spindle supports 2 and rotate freely about the spindles3. Referring also to FIG. 11, the spindle rollers 4 and the ends of thespindles 3 fit inside grooves 6 that are cut into a pair of stationarysupports 5 a, 5 b.

Referring to FIGS. 4, 5 and 11, the stationary supports 5 a, 5 b aregenerally in the form of parallel disks annularly located about the axisof the transmission on either side of the power adjusters 1. As therotational axes of the speed adjusters 1 are changed by moving thespindle supports 2 radially out from the axis of the transmission 100 totilt the spindles 3, each spindle roller 4 fits into and follows agroove 6 cut into one of the stationary supports 5 a, 5 b. Any radialforce, not rotational but a transaxial force, the speed adjusters 1 mayapply to the spindles 3 is absorbed by the spindles 3, the spindlerollers 4 and the sides 81 of the grooves 6 in the stationary supports 5a, 5 b. The stationary supports 5 a, 5 b are mounted on a pair of splitshafts 98, 99 positioned along the axis of the transmission 100. Thesplit shafts 98, 99 are generally elongated cylinders that define asubstantial portion of the axial length of the transmission 100 and canbe used to connect the transmission 100 to the object that uses it. Eachof the split shafts 98, 99 has an inside end near the middle of thetransmission 100 and an outside end that extends out of the internalhousing of the transmission 100. The split shafts 98, 99 are preferablyhollow so as to house other optional components that may be implemented.The stationary supports 5 a, 5 b, each have a bore 82, through which thesplit shafts 98, 99 are inserted and rigidly attached to prevent anyrelative motion between the split shafts 98, 99 and the stationarysupports 5 a, 5 b. The stationary supports 5 a, 5 b are preferablyrigidly attached to the ends of the split shafts 98, 99 closest to thecenter of the transmission 100. A stationary support nut 90 may bethreaded over the split shaft 99 and tightened against the stationarysupport 5 b on corresponding threads of the stationary support 5 a, 5 b.The grooves 6 in the stationary supports 5 a, 5 b referred to above,extend from the outer circumference of the stationary supports 5 a, 5 bradially inwardly towards the split shafts 98, 99. In most embodiments,the groove sides 81 of the grooves 6 are substantially parallel to allowthe spindle rollers 4 to roll up and down the groove sides 81 as thetransmission 100 is shifted. Also, in certain embodiments, the depth ofthe grooves 6 is substantially constant at the circumference 9 of thestationary supports 5 a, 5 b, but the depth of the grooves 6 becomesshallower at points 7 closer to the split shaft 98, 99, to correspond tothe arc described by the ends of the spindles 3 as they are tilted, andto increase the strength of the stationary supports 5 a, 5 b. As thetransmission 100 is shifted to a lower or higher transmission ratio bychanging the rotational axes of the speed adjusters 1, each one of thepairs of spindle rollers 4, located on the opposite ends of a singlespindle 3, move in opposite directions along their corresponding grooves6.

Referring to FIGS. 9 and 11, stationary support wheels 30 can beattached to the spindle supports 2 with stationary support wheel pins 31or by any other attachment method. The stationary support wheels 30 arecoaxially and slidingly mounted over the stationary support wheel pins31 and secured with standard fasteners, such as ring clips for example.In certain embodiments, one stationary support wheel 30 is positioned oneach side of a spindle 2 with enough clearance to allow the stationarysupport wheels 30 to roll radially on concave surfaces 84 of thestationary supports 5 a, 5 b when the transmission 100 is shifted. Incertain embodiments, the concave surfaces 84 are concentric with thecenter of the speed adjusters 1.

Referring to FIGS. 2, 3, and 11, a plurality of elongated spacers 8 aredistributed radially about, and extend generally coaxially with, theaxis of the transmission. The elongated spacers 8 connect the stationarysupports 5 a to one another to increase the strength and rigidity of theinternal structure of the transmission 100. The spacers 8 are orientedgenerally parallel to one another, and in some embodiments, each oneextends from a point at one stationary support 5 a near the outercircumference to a corresponding point on the other stationary support 5b. The spacers 8 can also precisely fix the distance between thestationary supports 5 a, 5 b, align the grooves 6 of the stationarysupports 5 a, 5 b, ensure that the stationary supports 5 a, 5 b areparallel, and form a connection between the split shafts 98, 99. In oneembodiment, the spacers 8 are pressed through spacer holes 46 in thestationary supports 5 a, 5 b. Although eight spacers 8 are illustrated,more or less spacers 8 can be used. In certain embodiments, the spacers8 are located between two speed adjusters 1.

Referring to FIGS. 1, 3, and 13, the stationary support 5 a, in certainembodiments, is rigidly attached to a stationary support sleeve 42located coaxially around the split shaft 98, or alternately, isotherwise rigidly attached to or made an integral part of the splitshaft 98. The stationary sleeve 42 extends through the wall of the hubshell 40 and attaches to a frame support 15. In some embodiments, theframe support 15 fits coaxially over the stationary sleeve 42 and isrigidly attached to the stationary sleeve 42. The frame support 15 usesa torque lever 43, in some embodiments, to maintain the stationaryposition of the stationary sleeve 42. The torque lever 43 providesrotational stability to the transmission 100 by physically connectingthe stationary sleeve 42, via the frame support 15, and therefore therest of the stationary parts to a fixed support member of the item towhich the transmission 100 is to be mounted. A torque nut 44 threadsonto the outside of the stationary sleeve 42 to hold the torque lever 43in a position that engages the frame support 15. In certain embodiments,the frame support 15 is not cylindrical so as to engage the torque lever43 in a positive manner thereby preventing rotation of the stationarysleeve 42.

For example, the frame support 15 could be a square of thickness equalto the torque lever 43 with sides larger than the stationary sleeve andwith a hole cut out of its center so that the square may fit over thestationary sleeve 42, to which it may then be rigidly attached.Additionally, the torque lever 43 could be a lever arm of thicknessequal to that of the frame support 15 with a first end near the framesupport 15 and a second end opposite the first. The torque lever 43, insome embodiments, also has a bore through one of its ends, but this boreis a square and is a slightly larger square than the frame support 15 sothe torque lever 43 could slide over the frame support 15 resulting in arotational engagement of the frame support 15 and the torque lever 43.Furthermore, the lever arm of the torque lever 43 is oriented so thatthe second end extends to attach to the frame of the bike, automobile,tractor or other application that the transmission 100 is used upon,thereby countering any torque applied by the transmission 100 throughthe frame support 15 and the stationary sleeve 42. A stationary supportbearing 48 fits coaxially around the stationary sleeve 42 and axiallybetween the outside edge of the hub shell 40 and the torque lever 43.The stationary support bearing 48 supports the hub shell 40, permittingthe hub shell 40 to rotate relative to the stationary support sleeve 42.

Referring to FIGS. 1 and 10, in some embodiments, shifting is manuallyactivated by rotating a rod 10, positioned in the hollow split shaft 98.A worm screw 11, a set of male threads in some embodiments, is attachedto the end of the rod 10 that is in the center of the transmission 100,while the other end of the rod 10 extends axially to the outside of thetransmission 100 and has male threads affixed to its outer surface. Inone embodiment, the worm screw 11 is threaded into a coaxial sleeve 19with mating threads, so that upon rotation of the rod 10 and worm screw11, the sleeve 19 moves axially. The sleeve 19 is generally in the shapeof a hollow cylinder that fits coaxially around the worm screw 11 androd 10 and has two ends, one near stationary support 5 a and one nearstationary support 5 b. The sleeve 19 is affixed at each end to aplatform 13, 14. The two platforms 13, 14 are each generally of the formof an annular ring with an inside diameter, which is large enough to fitover and attach to the sleeve 19, and is shaped so as to have two sides.The first side is a generally straight surface that dynamically contactsand axially supports the support member 18 via two sets of contactbearings 17 a, 17 b. The second side of each platform 13, 14 is in theform of a convex surface. The platforms 13, 14 are each attached to oneend of the outside of the sleeve 19 so as to form an annular trougharound the circumference of the sleeve 19. One platform 13 is attachedto the side nearest stationary support 5 a and the other platform 14 isattached to the end nearest stationary support 5 b. The convex surfaceof the platforms 13, 14 act as cams, each contacting and pushingmultiple shifting wheels 21. To perform this camming function, theplatforms 13, 14 preferably transition into convex curved surfaces 97near their perimeters (farthest from the split shafts 98, 99), that mayor may not be radii. This curve 97 contacts with the shifting wheels 21so that as the platforms 13, 14 move axially, a shifting wheel 21 ridesalong the platform 13, 14 surface in a generally radial directionforcing the spindle support 2 radially out from, or in toward, the splitshaft 98, 99, thereby changing the angle of the spindle 3 and therotation axis of the associated speed adjuster 1. In certainembodiments, the shifting wheels 21 fit into slots in the spindlesupports 2 at the end nearest the centerline of the transmission 100 andare held in place by wheel axles 22.

Still referring to FIGS. 1 and 10, a support member 18 is located in thetrough formed between the platforms 13, 14 and sleeve 19, and thus movesin unison with the platforms 13, 14 and sleeve 19. In certainembodiments, the support member 18 is generally of one outside diameterand is generally cylindrical along the center of its inside diameterwith a bearing race on each edge of its inside diameter. In otherembodiments, the outer diameter of the support member 18 can benon-uniform and can be any shape, such as ramped or curved. The supportmember 18 has two sides, one near one of the stationary supports 5 a andone near the other stationary support 5 b. The support member 18 rideson two contact bearings 17 a, 17 b to provide rolling contact betweenthe support member 18 and the sleeve 19. The contact bearings 17 a, 17 bare located coaxially around the sleeve 19 where the sleeve 19intersects the platforms 13, 14 allowing the support member 18 to freelyrotate about the axis of the transmission 100. The sleeve 19 issupported axially by the worm screw 11 and the rod 10 and therefore,through this configuration, the sleeve 19 is able to slide axially asthe worm screw 11 positions it. When the transmission 100 is shifted,the sleeve 19 moves axially, and the bearings 17 a, 17 b, support member18, and platforms 13, 14, which are all attached either dynamically orstatically to the sleeve, move axially in a corresponding manner.

In certain embodiments, the rod 10 is attached at its end opposite theworm screw 11 to a shifting tube 50 by a rod nut 51, and a rod flange52. The shifting tube 50 is generally in the shape of a tube with oneend open and one end substantially closed. The open end of shifting tube50 is of a diameter appropriate to fit over the end of the split shaft98 that extends axially out of the center of the transmission 100. Thesubstantially closed end of the shifting tube 50 has a small borethrough it so that the end of the rod 10 that is opposite of the wormscrew 11 can pass through it as the shifting tube 50 is placed over theoutside of the split shaft 98. The substantially closed end of theshifting tube 50 can then be fixed in axial place by the rod nut 51,which is fastened outside of the shifting tube 50, and the rod flange52, which in turn is fastened inside of the shifting tube's 50substantially closed end, respectively. The shifting tube 50 can, insome embodiments, be rotated by a cable 53 attached to the outside ofthe shifting tube 50. The cable 53, in these embodiments, is attached tothe shifting tube 50 with a cable clamp 54 and cable screw 56, and thenwrapped around the shifting tube 50 so that when tension is applied tothe cable 53 a moment is developed about the center of the axis of theshifting tube 50 causing it to rotate. The rotation of shifting tube 50may alternately be caused by any other mechanism such as a rod, by handrotation, a servo-motor or other method contemplated to rotate the rod10. In certain embodiments, when the cable 53 is pulled so that theshifting tube 50 rotates clockwise on the split shaft 98, the worm screw11 rotates clockwise, pulling the sleeve 19, support member 18 andplatforms 13, 14, axially toward the shifting tube 50 and shifting thetransmission 100 towards a low transmission ratio. A worm spring 55, asillustrated in FIG. 3, that can be a conical coiled spring capable ofproducing compressive and torsional force, attached at the end of theworm screw 11, is positioned between the stationary support 5 b and theplatform 14 and resists the shifting of the transmission 100. The wormspring 55 is designed to bias the shifting tube 50 to rotate so as toshift the transmission 100 towards a low transmission ratio in someembodiments and towards a high transmission ratio in other embodiments.

Referring to FIGS. 1, 10, and 11, axial movement of the platforms 13,14, define the shifting range of the transmission 100. Axial movement islimited by inside faces 85 on the stationary supports 5 a, 5 b, whichthe platforms 13, 14 contact. At an extreme high transmission ratio,platform 14 contacts the inside face 85 on one of the stationarysupports 5 a, 5 b, and at an extreme low transmission ratio, theplatform 13 contacts the inside face 85 on the other one of thestationary supports 5 a, 5 b. In many embodiments, the curvature of theconvex radii of the platforms 13, 14, are functionally dependant on thedistance from the center of a speed adjuster 1 to the center of thewheel 21, the radius of the wheel 21, the distance between the twowheels 21 that are operably attached to each speed adjuster 1, and theangle of tilt of the speed adjuster 1 axis.

Although a left hand threaded worm screw 11 is disclosed, a right handthreaded worm screw 11, the corresponding right hand wrapped shiftingtube 50, and any other combination of components just described that iscan be used to support lateral movement of the support member 18 andplatforms 13, 14, can be used. Additionally, the shifting tube 50 canhave internal threads that engage with external threads on the outsideof the split shaft 98. By adding this threaded engagement, the shiftingtube 50 will move axially as it rotates about the split shaft 98 causingthe rod 10 to move axially as well. This can be employed to enhance theaxial movement of the sleeve 19 by the worm screw 11 so as to magnifythe effects of rotating the worm screw 11 to more rapidly shift the gearratio or alternatively, to diminish the effects of rotating the wormscrew 11 so as to slow the shifting process and produce more accurateadjustments of the transmission 100.

Referring to FIGS. 10 and 18, manual shifting may be accomplished by useof a rotating handlegrip 132, which can be coaxially positioned over astationary tube, a handlebar 130, or some other structural member. Incertain embodiments, an end of the cable 53 is attached to a cable stop133, which is affixed to the rotating handlegrip 132. In someembodiments, internal forces of the transmission 100 and the conicalspring 55 tend to bias the shifting of the transmission towards a lowertransmission ratio. As the rotating handlegrip 132 is rotated by theuser, the cable 53, which can be wrapped along a groove around therotating handlegrip 132, winds or unwinds depending upon the directionof rotation of the cable 53, simultaneously rotating the shifting tube50 and shifting the transmission 100 towards a higher transmissionratio. A set of ratchet teeth 134 can be circumferentially positioned onone of the two sides of the rotating handlegrip 132 to engage a matingset of ratchet teeth on a first side of a ratcheted tube 135, therebypreventing the rotating handlegrip 132 from rotating in the oppositedirection. A tube clamp 136, which can bean adjustable screw allowingfor variable clamping force, secures the ratcheted tube 135 to thehandlebar 130. When shifting in the opposite direction, the rotatinghandlegrip 132, is forcibly rotated in the opposite direction toward alower transmission ratio, causing the tube clamp 136 to rotate in unisonwith the rotating handlegrip 132. A handlebar tube 137, positionedproximate to the ratcheted tube 135, on a side opposite the ratchetteeth 134, is rigidly clamped to the handlebar 130 with a tube clamp138, thereby preventing disengagement of the ratcheted tube 135 from theratchet teeth 134. A non-rotating handlegrip 131 is secured to thehandlebar 130 and positioned proximate to the rotating handlegrip 132,preventing axial movement of the rotating handlegrip 132 and preventingthe ratchet teeth 134 from becoming disengaged from the ratcheted tube135.

Now referring to embodiments illustrated by FIGS. 1, 9, and 11, a one ormore stationary support rollers 30 can be attached to each spindlesupport 2 with a roller pin 31 that is inserted through a hole in eachspindle support 2. The roller pins 31 are of the proper size and designto allow the stationary support rollers 30 to rotate freely over eachroller pin 31. The stationary support rollers 30 roll along concavecurved surfaces 84 on the sides of the stationary supports 5 a, 5 b thatface the speed adjusters 1. The stationary support rollers 30 provideaxial support to prevent the spindle supports 2 from moving axially andalso to ensure that the spindles 2 tilt easily when the transmission 100is shifted.

Referring to FIGS. 1, 12, 14, and 17, a three spoked drive disk 34,located adjacent to the stationary support 5 b, partially encapsulatesbut generally does not contact the stationary support 5 b. The drivedisk 34 may have two or more spokes or may be a solid disk. The spokesreduce weight and aid in assembly of the transmission 100 ineembodiments using them, however a solid disk can be used. The drive disk34 has two sides, a first side that contacts with the speed adjusters 1,and a second side that faces opposite of the first side. The drive disk34 is generally an annular disk that fits coaxially over, and extendsradially from, a set of female threads or nut 37 at its inner diameter.The outside diameter of the drive disk 34 is designed to fit within thehub shell 40, if the hub shell 40 employed is the type that encapsulatesthe speed adjusters 1 and the drive disk 34, and engages with the hubcap 67. The drive disk 34 is rotatably coupled to the speed adjusters 1along a circumferential bearing surface on the lip of the first side ofthe drive disk 34. As mentioned above, some embodiments of the drivedisk 34 have a set of female threads 37, or a nut 37, at its center, andthe nut 37 is threaded over a screw 35, thereby engaging the drive disk34 with the screw 35. The screw 35 is rigidly attached to a set ofcentral screw ramps 90 that are generally a set of raised surfaces on anannular disk that is positioned coaxially over the split shaft 99. Thecentral screw ramps 90 are driven by a set of central drive shaft ramps91, which are similarly formed on a generally annular disk. The rampsurfaces of the central drive ramps 91 and the central screw ramps 90can be linear, but can be any other shape, and are in operable contactwith each other. The central drive shaft ramps 91, coaxially and rigidlyattached to the drive shaft 69, impart torque and an axial force to thecentral screw ramps 90 that can then be transferred to the drive disk34. A central drive tension member 92, positioned between the centraldrive shaft ramps 91 and the central screw ramps 90, produces torsionaland/or compressive force, ensuring that the central ramps 90, 91 are incontact with one another.

Still referring to FIGS. 1, 12, 14, and 17, the screw 35, which iscapable of axial movement, can be biased to move axially away from thespeed adjusters 1 with an annular thrust bearing 73 that contacts a raceon the side of the screw 35 that faces the speed adjusters 1. An annularthrust washer 72, coaxially positioned over the split shaft 99, contactsthe thrust bearing 73 and can be pushed by a pin 12 that extends througha slot in the split shaft 99. A compression member 95 capable ofproducing a compressive force is positioned in the bore of the hollowsplit shaft 99 at a first end. The compression member 95, which may be aspring, contacts the pin 12 on one end, and at a second end contacts therod 10. As the rod 10 is shifted towards a higher transmission ratio andmoves axially, it contacts the compression member 95, pushing it againstthe pin 12. Internal forces in the transmission 100 will bias thesupport member 18 to move towards a high transmission ratio positiononce the transmission ratio goes beyond a 1:1 transmission ratio towardshigh and the drive disk 34 rotates more slowly than the hub shell 40.This bias pushes the screw 35 axially so that it either disconnects fromthe nut 37 and no longer applies an axial force or a torque to the drivedisk 34, or reduces the force that the screw 35 applies to the nut 37.In this situation, the percentage of axial force applied to the drivedisk 34 by the perimeter ramps 61 increases. It should be noted that theinternal forces of the transmission 100 will also bias the supportmember 18 towards low once the support member 18 passes beyond aposition for a 1:1 transmission ratio towards low and the hub shell 40rotates more slowly than the drive disk 34. This beneficial bias assistsshifting as rpm's drop and torque increases when shifting into low.

Still referring to FIGS. 1, 12, 14, and 17, the drive shaft 69, which isa generally tubular sleeve having two ends and positioned coaxial to theoutside of the split shaft 99, has at one end the aforementioned centraldrive shaft ramps 91 attached to it, while the opposite end faces awayfrom the drive disk 34. In certain embodiments, a bearing disk 60 isattached to and driven by the drive shaft 69. The bearing disk 60 can besplined to the drive shaft 69, providing for limited axial movement ofthe bearing disk 60, or the bearing disk 60 can be rigidly attached tothe drive shaft 69. The bearing disk 60 is generally a radial diskcoaxially mounted over the drive shaft 69 extending radially outward toa radius generally equal to that of the drive disk 34. The bearing disk60 is mounted on the drive shaft 69 in a position near the drive disk34, but far enough away to allow space for a set of perimeter ramps 61,associated ramp bearings 62, and a bearing race 64, all of which arelocated between the drive disk 34 and the bearing disk 67. In certainembodiments, the plurality of perimeter ramps 61 can be concave and arerigidly attached to the bearing disk 60 on the side facing the drivedisk 34. Alternatively, the perimeter ramps 61 can be convex or linear,depending on the use of the transmission 100. Alternatively, the bearingrace 64, can be replaced by a second set of perimeter ramps 97, whichmay also be linear, convex, or concave, and which are rigidly attachedto the drive disk 34 on the side facing the bearing disk 60. The rampbearings 62 are generally a plurality of bearings matching in number theperimeter ramps 61. Each one of the plurality of ramp bearings 62 islocated between one perimeter ramp 61 and the bearing race 64, and isheld in its place by a compressive force exerted by the ramps 61 andalso by a bearing cage 63. The bearing cage 63 is an annular ringcoaxial to the split shaft 99 and located axially between the concaveramps 61 and convex ramps 64. The bearing cage 63 has a relatively largeinner diameter so that the radial thickness of the bearing cage 63 isonly slightly larger than the diameter of the ramp bearings 62 to housethe ramp bearings 62. Each of the ramp bearings 62 fits into a hole thatis formed in the radial thickness of the bearing cage 63 and theseholes, together with the previously mentioned compressive force, holdthe ramp bearings 62 in place. The bearing cage 63, can be guided intoposition by a flange on the drive disk 34 or the bearing disk 60, whichis slightly smaller than the inside diameter of the bearing cage 63.

Referring to FIGS. 1, 6, 7, 8, and 15, the bearing disk 60, theperimeter ramps 61, and a ramp bearing 62 of one embodiment aredepicted. Referring specifically to FIG. 6, a schematic view shows aramp bearing 62 contacting a concave perimeter ramp 61, and a secondconvex perimeter ramp 97. Referring specifically to FIG. 7, a schematicview shows the ramp bearing 62, the concave perimeter ramp 61, and thesecond convex perimeter ramp 97 of FIG. 6 at a different torque ortransmission ratio. The position of the ramp bearings 62 on theperimeter ramps 61 depicted in FIG. 7 produces less axial force than theposition of the ramp bearings 62 on the perimeter ramps 61 depicted inFIG. 6. Referring specifically to FIG. 8, a ramp bearing 62 is showncontacting a convex perimeter ramp 61, and a concave second perimeterramp 97 in substantially central positions on those respective ramps. Itshould be noted that changes in the curves of the perimeter ramps 61, 97change the magnitude of the axial force applied to the power adjusters 1at various transmission ratios, thereby maximizing efficiency indifferent gear ratios and changes in torque. Depending on the use forthe transmission 100, many combinations of curved or linear perimeterramps 61, 97 can be used. To simplify operation and reduce cost, in someapplications one set of perimeter ramps may be eliminated, such as thesecond set of perimeter tramps 97, which are then replaced by a bearingrace 64. To further reduce cost, the set of perimeter ramps 61 may havea linear inclination.

Referring to FIG. 1, a coiled spring 65 having two ends wraps coaxiallyaround the drive shaft 69 and is attached at one end to the bearing disk60 and at its other end to the drive disk 34. The coiled spring 65provides force to keep the drive disk 34 in contact with the speedadjusters 1 and biases the ramp bearings 62 up the perimeter ramps 61.The coiled spring 65 is designed to minimize the axial space withinwhich it needs to operate and, in certain embodiments, the cross sectionof the coiled spring 65 is a rectangle with the radial length greaterthan the axial length.

Referring to FIG. 1, the bearing disk 60 preferably contacts an outerhub cap bearing 66 on the bearing disk 60 side that faces opposite theconcave ramps 61. The outer hub cap bearing 66 can be an annular set ofroller bearings located radially outside of, but coaxial with, thecenterline of the transmission 100. The outer hub cap bearing 66 islocated radially at a position where it may contact both the hub cap 67and the bearing disk 60 to allow their relative motion with respect toone another. The hub cap 67 is generally in the shape of a disk with ahole in the center to fit over the drive shaft 69 and with an outerdiameter such that it will fit within the hub shell 40. The innerdiameter of the hub cap engages with an inner hub cap bearing 96 that ispositioned between the hub cap 67 and the drive shaft 69 and maintainsthe radial and axial alignment of the hub cap 67 and the drive shaft 69with respect to one another. The edge of the hub cap 67 at its outerdiameter can be threaded so that the hub cap 67 can be threaded into thehub shell 40 to encapsulate much of the transmission 100. A sprocket orpulley 38 or other drive train adapter, such as gearing for example, canbe rigidly attached to the rotating drive shaft 69 to provide the inputrotation. The drive shaft 69 is maintained in its coaxial position aboutthe split shaft 99 by a cone bearing 70. The cone bearing 70 is anannular bearing mounted coaxially around the split shaft 99 and allowsrolling contact between the drive shaft 69 and the split shaft 99. Thecone bearing 70 may be secured in its axial place by a cone nut 71 whichthreads onto the split shaft 99 or by any other fastening method.

In operation of certain embodiments, an input rotation from the sprocketor pulley 38 is transmitted to the drive shaft 69, which in turn rotatesthe bearing disk 60 and the plurality of perimeter ramps 61 causing theramp bearings 62 to roll up the perimeter ramps 61 and press the drivedisk 34 against the speed adjusters 1. The ramp bearings 62 alsotransmit rotational energy to the drive disk 34 as they are wedged inbetween, and therefore transmit rotational energy between, the perimeterramps 61 and the convex ramps 64. The rotational energy is transferredfrom the drive disk 34 to the speed adjusters 1, which in turn rotatethe hub shell 40 providing the transmission 100 output rotation andtorque.

Referring to FIG. 16, a latch 115 rigidly attaches to the side of thedrive disk 34 that faces the bearing disk 60 and engages a hook 114 thatis rigidly attached to a first of two ends of a hook lever 113. Theengaging area under the latch 115 opening is larger than the width ofthe hook 114 and provides extra room for the hook 114 to move radially,with respect to the axis, within the confines of the latch 114 when thedrive disk 34 and the bearing disk 60 move relative to each other. Thehook lever 113 is generally a longitudinal support member for the hook114 and at its second end, the hook lever 113 has an integral hook hinge116 that engages with a middle hinge 119 via a first hinge pin 111. Themiddle hinge 119 is integral with a first end of a drive disk lever 112,a generally elongated support member having two ends. On its second end,the drive disk lever 112 has an integral drive disk hinge 117, whichengages a hinge brace 110 via the use of a second hinge pin 118. Thehinge brace 110 is generally a base to support the hook 114, the hooklever 113, the hook hinge 116, the first hinge pin 111, the middle hinge119, the drive disk lever 112 the second hinge pin 118, and the drivedisk hinge 117, and it is rigidly attached to the bearing disk 60 on theside facing the drive disk 34. When the latch 73 and hook 72 are engagedthe ramp bearings 62 are prevented from rolling to an area on theperimeter ramps 61 that does not provide the correct amount of axialforce to the drive disk 34. This ensures that all rotational forceapplied to the ramp bearings 62 by perimeter ramps 61 is transmitted tothe drive disk 34.

Referring to FIGS. 1 and 17, a disengagement mechanism for oneembodiment of the transmission 100 is described to disengage the drivedisk 34 from the speed adjusters 1 in order to coast. On occasions thatinput rotation to the transmission 100 ceases, the sprocket or pulley 38stops rotating but the hub shell 40 and the speed adjusters 1 cancontinue to rotate. This causes the drive disk 34 to rotate so that theset of female threads 37 in the bore of the drive disk 34 wind onto themale threaded screw 35, thereby moving the drive disk 34 axially awayfrom the speed adjusters 1 until the drive disk 34 no longer contactsthe speed adjusters 1. A toothed rack 126, rigidly attached to the drivedisk 34 on the side facing the bearing disk 60, has teeth that engageand rotate a toothed wheel 124 as the drive disk 34 winds onto the screw35 and disengages from the power adjusters 1. The toothed wheel 124, hasa bore in its center, through which a toothed wheel bushing 121 islocated, providing for rotation of the toothed wheel 124. Clips 125 thatare coaxially attached over the toothed wheel bushing 121 secure thetoothed wheel 124 in position, although any means of fastening may beused. A preloader 120, coaxially positioned over and clamped to thecentral drive shaft ramps 91, extends in a direction that is radiallyoutward from the center of the transmission 100. The preloader 120, of aresilient material capable of returning to its original shape whenflexed, has a first end 128 and a second end 127. The first end of thepreloader 128 extends through the toothed wheel bushing 121 andterminates in the bearing cage 63. The first end of the preloader 128biases the bearing cage 63 and ramp bearings 62 up the ramps 61,ensuring contact between the ramp bearings 62 and the ramps 61, and alsobiases the toothed wheel 124 against the toothed rack 126. A pawl 123,engages the toothed wheel 124, and in one embodiment engages the toothedwheel 124 on a side substantially opposite the toothed rack 126. Thepawl 123 has a bore through which a pawl bushing 122 passes, allowingfor rotation of the pawl 123. Clips 125, or other fastening means securethe pawl 123 to the pawl bushing 121. A pawl spring 122 biases rotationof the pawl 123 to engage the toothed wheel 124, thereby preventing thetoothed wheel 124 from reversing its direction of rotation when thedrive disk 34 winds onto the screw 35. The pawl bushing 121 ispositioned over a second end of the preloader 127, which rotates inunison with the drive shaft 69.

Referring again to FIG. 1, a coiled spring 65, coaxial with and locatedaround the drive shaft 69, is located axially between and attached bypins or other fasteners (not shown) to both the bearing disk 60 at oneend and drive disk 34 at the other end. In certain embodiments, thecoiled spring 65 replaces the coiled spring of the prior art so as toprovide more force and take less axial space in order to decrease theoverall size of the transmission 100. In some embodiments, the coiledspring 65 is produced from spring steel wire with a rectangular profilethat has a radial length or height greater than its axial length orwidth. During operation of the transmission 100, the coiled spring 65ensures contact between the speed adjusters 1 and the drive disk 34.However, once the drive disk 34 has disengaged from the speed adjusters1, the coiled spring 65 is prevented from winding the drive disk 34 sothat it again contacts the speed adjusters 1 by the engagement of thetoothed wheel 124 and the pawl 123. When the input sprocket, gear, orpulley 38, resumes its rotation, the pawl 123 also rotates, allowing thetoothed wheel 124 to rotate, thus allowing the drive disk 34 to rotateand unwind from the screw 35 due to the torsional force created by thecoiled spring 65. Relative movement between the pawl 123 and the toothedwheel 124 is provided by the fact that the first end of the preloader128 rotates at approximately half the speed as the second end of thepreloader 127 because the first end of the preloader 128 is attached tothe bearing cage 63. Also, because the ramp bearings 62 are rolling onthe perimeter ramps 61 of the bearing disk 60, the bearing cage 63 willrotate at half the speed as the bearing disk 60.

Referring now to FIG. 19, an alternative embodiment of the transmission100 of FIG. 1 is disclosed. In this embodiment, an output disk 201replaces the hub shell 40 of the transmission 100 illustrated in FIG. 1.Similar to the drive disk 34, the output disk 201 contacts, and isrotated by, the speed adjusters 1. The output disk 201 is supported byan output disk bearing 202 that contacts both the output disk 201 and astationary case cap 204. The case cap 204 is rigidly attached to astationary case 203 with case bolts 205 or any other fasteners. Thestationary case 203 can be attached to a non-moving object such as aframe or to the machine for which its use is employed. A gear, sprocket,or pulley 206 is attached coaxially over and rigidly to the output disk201 outside of the case cap 204 and stationary case 203. Any other typeof output means can be used however, such as gears for example. Atorsional brace 207 can be added that rigidly connects the split shaft98 to the case cap 204 for additional support.

Referring now to FIGS. 20 and 21, an alternative embodiment of thetransmission 100 of FIG. 1 is disclosed. A stationary support race 302is added on a side of stationary support 5 a facing away from the speedadjusters 1 and engages with a stationary support bearing 301 and arotating hub shell race 303 to maintain correct alignment of thestationary support 5 a with respect to the rotating hub shell 40. Atorsional brace 304 is rigidly attached to the stationary support 5 aand can then be rigidly attached to a stationary external component toprevent the stationary supports 5 a, 5 b from rotating during operationof the transmission 300. A drive shaft bearing 306 is positioned at anend of the drive shaft 69 facing the speed adjusters 1 and engages adrive shaft race 307 formed in the same end of the drive shaft 69 and asplit shaft race 305 formed on a radially raised portion of the splitshaft 99 to provide additional support to the drive shaft 69 and toproperly position the drive shaft 69 relative to the stationary supports5 a, 5 b.

Referring now to FIGS. 22 and 23, an alternative disengagement mechanism400 of the transmission 100 of FIG. 1 is disclosed. A toothed wheel 402is coaxially positioned over a wheel bushing 408 and secured in positionwith a clip 413 or other fastener such that it is capable of rotation.The wheel bushing 408 is coaxially positioned over the first end of apreloader 405 having first and second ends (both not separatelyidentified in FIGS. 22, and 23). The preloader 405 clamps resilientlyaround the central drive shaft ramps 91. The first end of the preloader405 extends into the bearing cage 63, biasing the bearing cage 63 up theperimeter ramps 61. Also positioned over the wheel bushing 408 is alever 401 that rotates around the wheel bushing 408 and that supports atoothed wheel pawl 411 and a pinion pawl 409. The toothed wheel pawl 411engages the toothed wheel 402 to control its rotation, and is positionedover a toothed wheel bushing 414 that is pressed into a bore in thelever 401. A toothed wheel pawl spring 412 biases the toothed wheel pawl411 against the toothed wheel 402. The pinion pawl 409, positionedsubstantially opposite the toothed wheel pawl 411 on the lever 401, iscoaxially positioned over a pinion pawl bushing 415 that fits intoanother bore in the lever 401 and provides for rotational movement ofthe pinion pawl 409. A pinion pawl spring 410 biases the pinion pawl 409against a pinion 403.

Referring now to FIGS. 1, 22 and 23, the pinion 403 has a bore at itscenter and is coaxially positioned over a first of two ends of a rodlever 404. The rod lever is an elongated lever that engages the pinionpawl 409 during coasting until input rotation of the sprocket, pulley,or gear 38 resumes. A bearing disk pin 406 that is affixed to thebearing disk 60 contacts a second end of the rod lever 404, uponrotation of the bearing disk 60, thereby pushing the rod lever 404against a drive disk pin 407, which is rigidly attached to the drivedisk 34. This action forces the first end of the rod lever 404 to swingaway from the toothed wheel 402, temporarily disconnecting the pinion403 from the toothed wheel 402, allowing the toothed wheel 402 torotate. A lever hook 401 is attached to the the lever 401 and contacts alatch (not shown) on the drive disk 34 and is thereby pushed back as thecoiled spring 65 biases the drive disk 34 to unwind and contact thespeed adjusters 1. During occasions that the input rotation of thesprocket, pulley, or gear 38 ceases, and the speed adjusters 1 continueto rotate, the drive disk 34 winds onto the screw 35 and disengages fromthe speed adjusters 1. As the drive disk 34 rotates, the drive disk pin407 disengages from the rod lever 404, which then swings the pinion 403into contact with the toothed wheel 402, preventing the drive disk 34from re-engaging the speed adjusters 1.

Referring to FIGS. 24 and 25, a sub-assembly of an alternative set ofaxial force generators 500 of the transmission 300 of FIG. 20 isdisclosed. When rotated by the input sprocket, gear, or pulley 38, asplined drive shaft 501 rotates the bearing disk 60, which may havegrooves 505 in its bore to accept and engage the splines 506 of thesplined drive shaft 501. The central drive shaft ramps 508 are rigidlyattached to the bearing disk 60 or the splined drive shaft 501 androtate the central screw ramps 507, both of which have bores that clearthe splines 506 of the splined drive shaft 501. The central tensionmember 92 (illustrated in FIG. 1) is positioned between the centraldrive shaft ramps 508 and the central screw ramps 507. A grooved screw502 having a grooved end and a bearing end is rotated by the centralscrew ramps 90 and has grooves 505 on its bearing end that are widerthan the splines 506 on the splined drive shaft 501 to provide a gapbetween the splines 506 and the grooves 505. This gap between thesplines 506 and the grooves 505 allows for relative movement between thegrooved screw 502 and/or bearing disk 60 and the splined drive shaft501. On occasions when the grooved screw 502 is not rotated by thecentral drive shaft ramps 508 and the central screw ramps 507, thesplines 506 of the splined drive shaft 501 contact and rotate thegrooves 505 on the grooved screw 502, thus rotating the grooved screw502. An annular screw bearing 503 contacts a race on the bearing end ofthe grooved screw 502 and is positioned to support the grooved screw 502and the splined drive shaft 501 relative to the axis of the split shaft99. The bore of the grooved screw 502 is slightly larger than theoutside diameter of the splined drive shaft 501 to allow axial androtational relative movement of the grooved screw 502. A screw cone race504 contacts and engages the annular screw bearing 503 and has a holeperpendicular to its axis to allow insertion of a pin 12. The pin 12engages the rod 10, which can push on the pin 12 and move the groovedscrew 502 axially, causing it to disengage from, or reduce the axialforce that it applies to, the nut 37.

Referring to FIG. 26, an alternative disengagement means 600 of thedisengagement means 400 of FIGS. 22 and 23 is disclosed. The lever 401is modified to eliminate the T-shape used to mount both the pinion pawl409 and the toothed wheel pawl 411 so that the new lever 601 has onlythe toothed wheel pawl 411 attached to it. A second lever 602, having afirst end and a second end. The pinion pawl 409 is operably attached tothe first end of the second lever 602. The second lever 602 has a firstbore through which the first end of the preloader 405 is inserted. Thesecond lever 602 is rotatably mounted over the first end of thepreloader 405. The second lever 602 has a second bore in its second endthrough which the second end of the preloader 603 is inserted. Whenrotation of the sprocket, gear, or pulley 38 ceases, the drive disk 34continues to rotate forward and wind onto the screw 36 until itdisengages from the speed adjusters 1. The first end of the preloader405 rotates forward causing the pinion pawl 409 to contact and rotatethe pinion 403 clockwise. This causes the toothed wheel 402 to rotatecounter-clockwise so that the toothed wheel pawl 411 passes over one ormore teeth of the toothed wheel 402, securing the drive disk 34 andpreventing it from unwinding off of the screw 36 and contacting thespeed adjusters 1. When rotation of the sprocket, gear, or pulley 38resumes, the second end of the preloader 603 rotates, contacting thesecond end of the second lever 602 causing the pinion pawl 409 to swingout and disengage from the pinion 403, thereby allowing the drive disk34 to unwind and reengage with the speed adjusters 1.

With this description in place, some of the particular improvements andadvantages of the present invention will now be described. Note that notall of these improvements are necessarily found in all embodiments ofthe invention.

Referring to FIG. 1, a current improvement in some embodiments includesproviding variable axial force to the drive disk 34 to respond todiffering loads or uses. This can be accomplished by the use of multipleaxial force generators. Axial force production can switch between ascrew 35 and a nut 37, with associated central drive shaft ramps 91 andscrew ramps 90, to perimeter ramps 61, 64. Or the screw 35, centralramps 90, 91, and perimeter ramps 61, 64 can share axial forceproduction. Furthermore, axial force at the perimeter ramps 61, 64 canbe variable. This can be accomplished by the use of ramps of variableinclination and declination, including concave and convex ramps.Referring to FIG. 1 and FIGS. 6-8 and the previous detailed description,an embodiment is disclosed where affixed to the bearing disk 60 is afirst set of perimeter ramps 61, which may be concave, with which theramp bearings 62 contact. Opposite the first set of perimeter ramps 61are a second set of perimeter ramps 97 that are attached to the drivedisk 34, which may be convex, and which are in contact with the rampbearings 62. The use of concave and convex ramps to contact the rampbearings 62 allows for non-linear increase or decrease in the axial loadupon the drive disk 34 in response to adjustments in the position of thespeed adjusters 1 and the support member 18.

Another improvement of certain embodiments includes positively engagingthe bearing disk 60 and the drive disk 34 to provide greater rotationaltransmission and constant axial thrust at certain levels of torquetransmission. Referring to an embodiment illustrated in FIG. 1 asdescribed above, this may be accomplished, for example, by the use ofthe hook 114 and latch 115 combination where the hook 114 is attached tothe bearing cage 63 that houses the ramp bearings 62 between the drivedisk 34 and the bearing disk 60, and the latch 115 is attached to thedrive disk 34 that engages with the hook 114 when the ramp bearings 62reach their respective limit positions on the ramp faces. Although suchconfiguration is provided for example, it should be understood that thehook 114 and the latch 115 may be attached to the opposite componentdescribed above or that many other mechanisms may be employed to achievesuch positive engagement of the bearing disk 60 and the drive disk 34 atlimiting positions of the ramp bearings 62.

A further improvement of certain embodiments over previous designs is adrive disk 34 having radial spokes (not separately identified), reducingweight and aiding in assembly of the transmission 100. In a certainembodiment, the drive disk 34 has three spokes equidistant from eachother that allow access to, among other components, the hook 114 and thelatch 115.

Another improvement of certain embodiments includes the use of threads35, such as acme threads, to move the drive disk 34 axially when thereis relative rotational movement between the drive disk 34 and thebearing disk 60. Referring to the embodiment illustrated in FIG. 1, athreaded male screw 35 may be threaded into a set of female threads 37,or a nut 37, in the bore of the drive disk 34. This allows the drivedisk 34 to disengage from the speed adjusters 1 when the drive disk 34ceases to provide input torque, such as when coasting or rolling inneutral, and also facilitates providing more or less axial force againstthe speed adjusters 1. Furthermore, the threaded male screw 35 is alsodesigned to transmit an axial force to the drive disk 34 via the set offemale threads 37.

Yet another improvement of certain embodiments over past inventionsconsists of an improved method of shifting the transmission to higher orlower transmission ratios. Again, referring to the embodimentillustrated in FIG. 1, this method can be accomplished by using athreaded rod 10, including, for example, a left hand threaded worm screw11 and a corresponding right hand threaded shifting tube 50, or sleeve,that operates remotely by a cable 53 or remote motor or other remotemeans. Alternatively, left-handed threads can be used for both the wormscrew 11 and the shifting tube, or a non-threaded shifting tube 50 couldbe used, and any combinations thereof can also be used as appropriate toaffect the rate of shifting the transmission 100 with respect to therate of rotation of the shifting tube 50. Additionally, a conical spring55 can be employed to assist the operator in maintaining the appropriateshifting tube 50 position. The worm screw 11 is preferably mated with athreaded sleeve 19 so as to axially align the support member 18 so thatwhen the worm screw 11 is rotated the support member 18 will moveaxially.

Another improvement of some embodiments over past inventions is thedisengagement mechanism for the transmission 100. The disengagementmechanism allows the input sprocket, pulley, or gear 38 to rotate inreverse, and also allows the transmission 100 to coast in neutral bydisengaging the drive disk 34 from the speed adjusters 1.

The foregoing description details certain embodiments of the invention.It will be appreciated, however, that no matter how detailed theforegoing appears in text, the invention can be practiced in many ways.As is also stated above, it should be noted that the use of particularterminology when describing certain features or aspects of the inventionshould not be taken to imply that the terminology is being re-definedherein to be restricted to including any specific characteristics of thefeatures or aspects of the invention with which that terminology isassociated. The scope of the invention should therefore be construed inaccordance with the appended claims and any equivalents thereof.

1. A drill press comprising: a power source of the drill press; acontinuously variable transmission coupled to the power source, thecontinuously variable transmission comprising: a plurality of speedadjusters; a drive disk frictionally contacting the speed adjusters; adriven disk frictionally contacting the speed adjusters; a supportmember between the drive disk and the driven disk and frictionallycontacting the speed adjusters; a bearing disk adapted to providerotational force to the drive disk; a threaded member on the drive disk;and a screw for engaging the threaded member, the screw positionedcoaxial with and about a longitudinal axis of the continuously variabletransmission.
 2. The drill press of claim 1, wherein the screw isadapted to receive thrust from a thrust bearing to bias the screw awayfrom the speed adjusters.
 3. The drill press of claim 1, furthercomprising: a drive shaft having a set of drive shaft ramps; a diskhaving a set of screw ramps, the disk operationally engaged to thescrew; and wherein the drive shaft ramps and screw ramps are adapted tooperationally engage one another.
 4. The drill press of claim 3, whereinthe screw and the threaded member transfer to the drive disk axial forceproduced by the drive shaft ramps and the screw ramps.
 5. The drillpress of claim 5, further comprising a tension member, positionedbetween the drive shaft ramps and the screw ramps, the tension memberadapted to maintain engagement of the drive shaft ramps and the screwramps:
 6. The drill press of claim 1, further comprising a set ofperimeter ramps attached to the bearing disk, the perimeter rampsadapted to produce an axial force that is transferred to the drive disk.7. The drill press of claim 6, further comprising a set of ramp bearingspositioned between the bearing disk and the drive disk, the rampbearings contacting the perimeter ramps.
 8. A drill press comprising: apower source of the drill press; a continuously variable transmissioncoupled to the power source, the continuously variable transmissioncomprising: a plurality of speed adjusters; a drive disk adapted tooperationally engage the speed adjusters; a bearing disk adapted toprovide rotational force to the drive disk; and a disengagementmechanism adapted to disengage the drive disk from the speed adjusters,the disengagement mechanism positioned between the bearing disk and thedrive disk.
 9. The drill press of claim 8, wherein the disengagementmechanism comprises a toothed wheel and a pawl adapted to prevent thedrive disk from rotating onto the speed adjusters until an input forceis applied to the transmission.
 10. The drill press of claim 9, whereinthe disengagement mechanism comprises at least two pawls.
 11. The drillpress of claim 9, the disengagement mechanism further comprising: athreaded connector functionally interposed between the drive disk andthe bearing disk; and wherein a rotation of the drive disk rotates thethreaded connector to disengage the drive disk from the speed adjusters.12. The drill press of claim 8, wherein the disengagement mechanismcomprises: a preloader having first and second ends, the first endadapted to rotate about an axis at a different rotational speed than thesecond end; a bearing cage; a toothed wheel, wherein said first endsupports the toothed wheel and engages the bearing cage; a pawl, whereinsaid second end supports the pawl such as to allow the pawl to engagethe toothed wheel to prevent the drive disk from engaging the speedadjusters until an input force is applied to the transmission.
 13. Thedrill press of claim 8, wherein the disengagement mechanism comprises: athreaded connector functionally interposed between the drive disk andthe bearing disk; and wherein a rotation of the drive disk rotates thethreaded connector to disengage the drive disk from the speed adjusters.14. The drill press of claim 13, wherein a rotation of the bearing diskcauses the threaded connector to rotate relative to the screw andthereby operationally engage the drive disk with the speed adjusters.15. The drill press of claim 13, wherein the threaded connector isadapted to apply an axial force to the drive disk.
 16. The drill pressof claim 13, further comprising a coiled spring adapted to engage thedrive disk with the speed adjusters upon supply of an input rotationinto the transmission.
 17. A drill press comprising: a power source ofthe drill press; a continuously variable transmission coupled to thepower source, the continuously variable transmission comprising: agenerally tubular split shaft coaxial with a longitudinal axis of thetransmission and having a threaded end; a rod having first and secondends and located coaxially within the split shaft; a worm screw attachedto the first end of the rod and having a set of external threads; asleeve having a set of internal threads that fit around and engage theexternal threads of the worm screw; and a shifting tube that engages thesecond end of the rod and has a set of internal threads that fit overand engage the threaded end of the split shaft.
 18. The drill press ofclaim 17, further comprising a worm spring adapted to bias the rotationof the rod.
 19. The drill press of claim 18, wherein the worm springcomprises a conical spring having a first end and a second end, whereinthe conical spring fits coaxially over the longitudinal axis of thetransmission and is attached at the first end to the rod and is attachedat the second end to a stationary object.
 20. The drill press of claim17, further comprising: a generally tubular grooved screw, coaxial withthe longitudinal axis, having a threaded outer surface, a longitudinallygrooved inner surface, and a bearing race on an inner diameter thereof;and an annular bearing in operable contact and coaxial with the bearingrace.